Atomic-scale surface morphology of ultrathin thermal oxide formed on Si 100/ surface

The atomic-scale surface roughness of thermal oxides formed on Si 100. were studied as a function of oxide film thickness up to 3.15 nm using non-contact mode atomic force microscopy NC-AFM.. The height deviation of the oxide surface is limited to within a single atomic-step height of 0.135 nm on a Si 100.surface below the thickness of about 1 nm, but above this thickness, it increases with an increase in thickness at 7008C and then decreases drastically by the oxidation at 9008C and becomes comparable with the surface roughness before the oxidation. Oscillations in surface roughness with constant amplitude and period intervals of 0.19 nm were observed in the thickness range studied. Surface morphologies are affected strongly by the oxidation temperature, while the interface structures are affected weakly by the oxidation temperature. The area where the layer-by-layer oxidation reaction occurs is on the order of 5 nm in diameter at 7008C and increases significantly with an increase in oxidation temperatures up to 8008C and 9008C. q2000 Elsevier Science B.V. All rights reserved